After clinical suspicion, the following investigations are performed:
1. Free T3 and T4 LevelsIn classical cases, both T3 and T4 are elevated.
2. Serum TSH LevelsSerum TSH levels are classically suppressed.
3. Radioactive Iodine or Technetium ScanUptake is not always increased, but the scan will show multifocal areas of different activity.
4. Thyroid AntibodiesAutoantibodies against microsomal thyroid cell antigens are present in 25% of cases.
The treatment of choice is Radioactive Iodine (I-131). The principle of this treatment is that the thyroid is the only tissue in the body to selectively uptake iodine. The radioactive iodine selectively kills the cells that take up the iodine without causing any harm to the body.
Surgery is used for large goitres that are causing compression or are cosmetically unacceptable.